1987 Ranger 2.3l Idle issues.

[ljones]

I found a egr solenoid that had a different base and made it work. The engine now has no egr codes. I also replaced the distributor and the PIP code is gone. I had one code left and it was the #42 o2 sensor indicates system rich. After consulting with my dad and the Haynes manual I decided to replace the fuel pressure regulator. Code 42 went away and the engine idles better. I'm waiting to see if this helps the MPG any. I also have a new CAT that has been on standby until I get the over rich problem fixed. Thanks for all the help I've received so far!

 

[ljones]

My MPG has went down again. I'm getting 11 in the city and 14-16 on the highway. I'm getting lost as I'm out of parts to replace. I was playing with it today trying to run it with the IAC unplugged to adjust it and it won't run at 500 rpm. It starts running really rough below 800 rpm, and eventually just dies. What would not let it idle down?

 

[ljones]

This truck was not running the barn for 13 years. When we pulled it out we replaced both the fuel pumps to get it going. It ran fine for two years around the farm. The first week on the road it got 19MPG in the city the second week it went to 15-16MPG and 19 on the highway. Every since then the MPG hasn't changed until I replaced the injectors and the pressure regulator. The idle issues started with the second motor and didn't stop on the rebuilt third one. Before it went in the barn it was getting low 20mpgs in the city.

 

[ljones]

It still is passing the code reader test with no codes.

 

[tomw]

From going back to #1. The engine is now getting bad fuel economy. Mpg is in the mid-upper teens where it used to be in the high teens. My 85 gets 22-25 easily. Lima 5-speed OD.
Bad mileage can be caused by 1)low tire pressure, 2)carrying a ton of sand gravel rocks or stuff in the bed, 3) leaking injectors(you have new), 4)bad ignition (you replaced dist- how bout the plugs & wires & rotor & cap?), 5)over enthusiastic computer which doesnt' know the actual temp 6)bad wires or grounds or connections that prevent going into closed loop(O2 is reporting rich ... that means its voltage is ~.9vdc meaning actually that there are no excess O2 molecules in the exhaust gas flow, they have all been used up burning the fuel, so there must be excess fuel ... Why? DUnno.), 7)plugged air filter, but with a good O2, you'll lose power as it will trim fuel flow to match ... as far as it can do so, 8)bad or low temp thermostat not getting engine warmed quickly, 9) dragging brakes, 10) slipping clutch or transmission, 11) incorrect reporting of actual miles traveled, 12) someone borrowing fuel, 13) well, I'll think of something...
tom

 

[swingjunkie]

Wow, sounds like you are about out of parts to swap. I have been working on my 1985 Ranger 2.3 Lima 5 speed auto with Overdrive. It too was a barn truck. From 2007 - 2014 it was driven under 500 miles. My issue was stuttering and loss of power at highway speed, and a wobbly idle and stall issue at take off. The truck was sucking down fuel like crazy. The truck has 47,000 miles on it but the cat was completely plugged. I verified this by removing the EGR valve and rigging a pressure gauge into the EGR-manifold tube. At idle I had 4 PSI back pressure in the exhaust, at 2000 RPM I had 15 PSI back pressure. Replacing the cat took care of the stuttering and loss of power at highway speed. It improved the stall and wobbly idle, but not completely. Did you ever install your new CAT?

As I said mine still had a wobbly idle and in looking around for a vacuum leak I discovered gas in the FPR vacuum line, and an occasional sput of gas out of the FPR with the vacuum line removed. The failed FPR was allowing gas to be sucked directly through the FPR into the intake. Result was a lot of black smoke and spew out the exhaust, which I originally suspected was bad valve seals. This may also have been the reason the cat was plugged. Your FPR has been replaced so this is likely not the issue for you. For me it fixed the problem. The thing runs great and while I have not checked mileage, my gas gauge is no longer dropping like a rock.
All that said I still have engine code 34 and 41 as you did. I've decided to forget the codes for now, so long as the truck keeps running as it is.

 

[ljones]

I took the cat converter off and let it run open header for a little while and it didn't improve. I took the cat the rest of the way off and its totally burned out on the inside. Its just a mini straight pipe. Could this be causing my problems?

 

[ljones]

I replaced the CAT and the idle is still surging. Last week I blocked the EGR off and the MPG went back up to 15-16 in the city.

 

[ljones]

I ordered a new ECU to see if that will help. After that I don't know what to replace.


Just a thought. The camshaft in this motor was from the previous one that was high mileage and had been rebuilt. The idle issues didn't start till the second motor. Could the cam be worn?

 

[ljones]

The new ECU didn't help. Sometimes it will hold 900 RPM pretty well, but if you do anything that loads the motor like turning the fan wide open or the headlights it freaks out and starts surging and wont stop until you accelerate. Other than the idle the motor runs great through the rest of the RPM range.

 

[ljones]

Here is a short video of it running.

http://m.youtube.com/watch?feature=youtu.be&v=eOjjDg_2FeU

 

[tomw]

Did not watch video, but note that a sticky or gummed IAC can cause wobbly idle, as can a bad MAP sensor.
tom

 

[ljones]

Those are both brand new.